基于微波光电导衰退法的新型少子寿命测量仪

A New Lifetime Measurement Instrument for Minority Carrier Based on Microwave Photoconductivity Decay Technique

本文在传统微波光电导衰退法的基础上,提出了一种可用于测量半导体少数载流子寿命的新型少子寿命测量仪。通过增加频移器和混频器,对高频微波探测信号进行调制和解调,得到包含了样品少子浓度信息的低频信号。同时介绍了测量仪的基本原理和测量装置的结构,并分别对仪器内部的微波源、激光器、频移器和混频器的原理和参数选择进行了探讨。实验表明:测量结果波形与理论预期波形相吻合,证实了测量仪的可行性;新的测量仪保持了传统方法非接触、无损伤的优点,并降低了系统检测设备的性能要求,提高了测量信噪比。

A new lifetime measurement instrument for minority carrier of semiconductor is proposed based on the traditional microwave photoconductivity decay technique. By adding the frequency shifter and mixer to make modulation and demodulation to the high-frequency microwave detecting signal, the low-frequency signal containing the information about the concentration of minority carder is obtained. The basic principle of measurement instrument is introduced, the structure is designed, the principle and parameter selections of microwave source, laser, frequency shifter and mixer inside the instrument are discussed respectively. Experiments show that the resultant waveform is consistent with the expected waveform, confirming the feasibility of the measurement instrument. The new measurement instrument keep the non-contact and non-destructive advantages of traditional method, and reduce the performance requirement for the detecting devices, improves the signal to noise ratio.